PROBLEM
The following symptoms occur on a KDB private storage server: -
- Available memory is almost exhausted.
- The system file cache consumes most of the physical RAM
- There is a continuous and high volume of cached read requests to the hard disk
Rebooting the system temporarily resolves the issue, but RAM usage continually increases until there is almost none available again.
CAUSE
This MS article describes how this situation arises, and how to identify it - https://support.microsoft.com/kb/976618
KDB may cause the cache to grow large because it creates a large number of small files in the backup store, especially if there are many agents backing up to the same storage server.
SOLUTION
Possible solutions include: -
1) add more physical RAM to the server
2) decrease the workload on the storage server (for example, by splitting backup agents among several storage servers)
3) avoid running other RAM intensive applications on the same server as the private storage server
4) as noted in the MS article linked above, there is a Windows utility to restrict the size of the cache. This will increase the amount of RAM available for other applications, but please note that it may decrease file system performance, which in turn may affect backup/restore times.
FURTHER INVESTIGATION
If further assistance is needed, please provide Kaseya support with the following information: -
1) screenshot from RAMmap utility showing use counts
2) number of agents backing up the storage server
3) troubleshooting steps taken so far
APPLIES TO
Kaseya VSA (all versions)
Data Backup (KDB)